Carrying apparatus and carrying control method for sheet-like substrate

ABSTRACT

The present invention relates to a transporting apparatus and a transporting control method for thin plates, the apparatus for transporting the thin plates such as liquid crystal display panels and glass plates into a processing chamber, comprising a rather large robot ( 14 ) having rotating arms ( 16 ) for transporting large-sized thin plates. The transporting apparatus and a thin plate transporting system can stably raise the plates up to the heights of approximately 2 m and can transporting the plates with the deflected amount of the extended rotating arms ( 16 ) compensated. A horizontal support table ( 13 ) liftably cantilevered on two upright support members ( 12 ) is provided in the apparatus, and the transporting robot ( 14 ) with the rotating arms ( 16 ) is placed on the horizontal support table ( 13 ). Also, the deflected amount of the extended rotating arms is compensated by raising the height of the horizontal support table ( 13 ) based on the deflected amount. The deflected amount can also be compensated by varying the installation angle of the robot ( 14 ) placed on the horizontal support table ( 13 ).

TECHNICAL FIELD

The present invention relates to a transporting apparatus and atransporting control method for thin plates, the transporting apparatusbeing installed in a given clean environment for transporting ortransferring the thin plates such as semiconductor wafers, liquidcrystal display units, plasma display units, organic electroluminescencedisplay units, inorganic electroluminescence display units, fieldemitting display units, liquid crystal display panels, printed-wiringassemblies, and partly-finished products.

BACKGROUND ART

Conventionally, used as a robot for transporting thin plates in theclean environment is a scalar type robot represented in the JapanesePatent No. 2,739,413. However, in these days, as display units such asliquid crystal display units (liquid crystal display TV) become largerin size, glass plates used therefor also become larger in size, whichrequires upsizing of a robot for transporting the plates. Accordingly,when glass plates are transported in and transferred to variousprocessing chambers, it is required to prepare a large-sized glass plateof 2 m×2 m or more in size, lift the plate up by 2 m or more andtransport the plate at high speed and accurately. Since a large-sizedthin plate (or glass plate) is heavy and vulnerable to deflection, it isdifficult to transport the heavy, large-sized thin plate upward, at highspeed and stably. In order to solve this problem, various inventionswere proposed.

For example, Japanese Laid-open Patent Publication No. Hei9-505384discloses a lifting mechanism having multistage ball screws, andJapanese Laid-open Patent Publication No. Hei10-209241 discloses ajack-type lifting mechanism. In addition, Japanese Laid-open PatentPublication No. Hei11-238779 discloses a jointed-arm type liftingmechanism used in robot welders and Japanese Laid-open PatentPublication No. 2001-274218 discloses a robot with a lifting mechanismarranged at the base of two horizontally rotating arms which are opposedvertically.

DISCLOSURE OF INVENTION

Problems to be Solved by the Invention

However, the multistage ball screw lifting mechanism has a difficulty inwithstanding the rolling since the mechanism is poor in strength in thehorizontal direction. For the jack-type or jointed-arm type robot, whenit brings up the plate against the gravity, much power is required basedon the reverse leverage. Further, in order to bear the burden of thispower, the arm driving mechanism is required to have a thick and heavyframework, which presents a problem. When a robot having one liftingmechanism at the base of horizontally rotating arms is used, freetransporting is permitted only at the arm-attached side. Therefore, inorder to transporting the plate to the opposite side, the liftingmechanism supporting the heavy weight has to be provided with onerotational axis at the bottom thereof to be rotated, which isstructurally difficult.

Further, when a robot becomes larger associated with upsizing of thinplates, the robot itself increases in weight and the distance ofextended end effectors becomes longer. This is likely to deflect therobot itself in operation (depending operational positions of the endeffectors), which makes it difficult to perform transporting operations,including taking out a thin plate of a cassette and inserting the thinplate into a cassette, without considering tilt of the robot bydeflection. Here, in the description of the specification of thisapplication, it is assumed that “transporting” of a thin plate from aposition A to a position B by a transporting robot means all movement ofa thin plate by the transporting robot. For example, “transporting”includes the operation of taking a thin plate out of a cassette totransport it to a processing chamber and the operation of taking a thinplate from the processing chamber back into a cassette,

Furthermore, when a large-sized, largely-deflected thin plate such asglass plate which is used as a plate of a liquid crystal display unit islifted and held by the end effectors, transported at a high speed andplaced on a given position, it is important to place the thin plate at agiven reference position properly. When the position where the thinplate is placed on the end effectors is displaced, it becomes difficultnot only to place the thin plate at a correct position but also toperceive the transporting path of the glass plate (thin plate) anddeflection accurately, which sometimes causes the thin plate to bebrought into contact with other mechanisms to be broken.

Accordingly, it is an object of the present invention to provide atransporting apparatus and a transporting system, the transportingapparatus installed in a given clean environment and capable ofproviding stable behavior in transporting a large-sized sheet mediumupward against the gravity, eliminating the necessity of large powerthat was required conventionally.

Further, it is another object of the present invention to provide atransporting apparatus and its transporting control method capable oftransporting a thin plate accurately even if a robot is deflected.

Furthermore, it is still another object of the present invention toprovide a transporting apparatus and its transporting control methodcapable of detecting whether a sheet medium is held at a properreference position and calculating displacement of the medium from theproper reference position so as to correct the transporting path.

Means for Solving the Problem

According to the present invention, a horizontal support table isprovided liftable between a pair of upright support members and a robotis placed on the horizontal support table, having horizontally rotatingarms. Further, a tilt adjusting mechanism is provided on the horizontalsupport table thereby to make the tilt angle of the robot adjustable.

According to a first embodiment of a transporting apparatus of thepresent invention, the transporting apparatus is installed in a givenclean environment, for transporting a large-sized thin plate from apredetermined takeoff position to a processing chamber, and comprises: apair of upright support members standing and being spaced; at least onehorizontal support table liftably cantilevered on the pair of uprightsupport members; lift driving means for lifting the horizontal supporttable vertically; and a robot placed on the horizontal support table andhaving horizontally rotating arms for taking up and transporting thethin plate.

In this embodiment, as the robot is supported by the two upright supportmembers and lifted vertically along the upright support members, stablelifting even to a relatively high position is allowed. In addition, aload added to raise the robot does not depend on the current position ofthe robot.

According to another embodiment of the transporting apparatus of thepresent invention, the transporting apparatus is characterized in thatthe robot drives the horizontally rotating arms to take the thin platefrom or back to between the pair of upright support members. In thisembodiment, as the spacing of the pair of upright support members is setto be larger than the width of the thin plate, it is possible to takethe thin plate from between the pair of upright support members.

According to another embodiment of the transporting apparatus of thepresent invention, the transporting apparatus is characterized in thatthe horizontal support table comprises tilt adjusting means for changingan angle of the robot placed on the horizontal support table withrespect to a horizontal plane. In this embodiment, as the tilt adjustingmeans is provided at the horizontal support table which the robot isplaced on so as to slightly change the tilt of the robot as a whole, itis possible to change the tilt of the robot. Tilt adjustment is allowedby, for example, taking up or down one point, two points or one side onthe table supporting the robot slightly by a cum.

According to another embodiment of the transporting apparatus of thepresent invention, the transporting apparatus is characterized byfurther comprising deflection compensating means for compensating adeflected amount in a vertical direction of the rotating arms and adeflected amount of end effectors provided at respective ends of therotating arms for taking up and transporting the thin plate. In thisembodiment, it is possible to compensate deflection caused by upsizingof the thin plate and increase in moving amount of the rotating armsthereby to hold the thin plate accurately and transport it to a targetposition precisely safely.

According to another embodiment of the transporting apparatus of thepresent invention, the transporting apparatus is characterized in thatthe deflection compensating means compensates both of the deflectedamounts when the end effectors take up the thin plate. In thisembodiment, compensation is controlled based on the deflected amountdepending on whether the thin plate is held or not.

According to another embodiment of the transporting apparatus of thepresent invention, the transporting apparatus is characterized in thatthe deflection compensating means comprises deflection storing means forstoring deflected amounts in the vertical direction at a plurality ofmeasurement points involved in movement of a reference point on therotating arms or the end effectors and, every time the reference pointmoves to one of the measurement points, the deflection compensatingmeans reads a deflected amount corresponding to a present position fromthe deflection storing means to compensate the deflected amount. In thisembodiment, it is possible to perform time-division compensation controlbased on the deflected amount which is changed with moving distance ofthe rotating arms. This further enables more efficient transportingoperation.

According to another embodiment of the transporting apparatus of thepresent invention, the transporting apparatus is characterized in thatthe deflection storing means stores both a deflected amount due to itsown weight (hereinafter also referred to as “self weight”) and adeflected amount due to holding of the thin plate, and the deflectedamount due to self weight and the deflected amount due to holding of thethin plate are used to change a compensation amount.

According to another embodiment of the transporting apparatus of thepresent invention, the transporting apparatus is characterized in thatthe deflection compensating means comprises compensation controllingmeans for controlling the lift driving means to raise or lower thehorizontal support table based on the deflected amount thereby tocompensate deflection of the rotating arms or the end effectors. In thisembodiment, deflection compensation is performed by adjusting the heightof the horizontal support table on which the robot is placed based onthe deflected amount.

According to another embodiment of the transporting apparatus of thepresent invention, the transporting apparatus is characterized in thatthe deflection compensating means comprises compensation controllingmeans for controlling the tilt adjusting means to tilt the robot placedon the horizontal support table so as to raise or lower the endeffectors or the rotating arms thereby to compensate deflection of therotating arms or the end effectors. In this embodiment, deflectioncompensation is performed by tilting the robot on the horizontal supporttable thereby to raise the position of ends of the end effectors.

According to another embodiment of the transporting apparatus of thepresent invention, the transporting apparatus is characterized in thatthe deflection compensating means comprises compensation controllingmeans for controlling the lift driving means and the tilt adjustingmeans so as to raise or lower the horizontal support table and/or tocontrol the tilt adjusting means to performed tilting based on thedeflected amount thereby to compensate deflection of the rotating armsor the end effectors. In this embodiment, deflection control is allowedby both of adjusting the vertical direction of the horizontal supporttable and adjusting the tilt of the robot. This enables appropriate andefficient transporting of the thin plate.

According to another embodiment of the transporting apparatus of thepresent invention, the transporting apparatus is characterized byfurther comprising: placing position detecting means including a placingposition sensor for detecting passage of the thin plate held by the endeffectors and calculating means for calculating a displaced amount ofthe placing position from the reference point based on a detected signalof the placing position sensor; and displacement compensating means forcompensating the displaced amount of the placing position based on thecalculated displaced amount. In this embodiment, as the displacement ofthe transporting position due to the displacement of the placingposition is prevented, the transporting operation can be performedaccurately. In addition, it is possible to prevent accidents such ascontacting with another portion due to displacement of the placingposition during transporting.

According to another embodiment of the transporting apparatus of thepresent invention, the transporting apparatus is characterized in thatthe placing position detecting means calculates a displaced amount in anX axis direction, a displaced amount in a Y axis direction and adisplaced amount in a rotational direction from the predeterminedreference point and the displacement compensating means compensates thedisplaced amounts by moving the end effectors in such a direction thatthe calculated displaced amounts are cancelled. In this embodiment, itis possible to compensate displacement of the placing position in all ofthe X direction, the Y axis direction and the rotational direction.

According to another embodiment of the transporting apparatus of thepresent invention, the transporting apparatus is characterized byfurther comprising moving means for moving the pair of upright supportmembers horizontally. In this embodiment, as the horizontal supporttable with the robot placed on is configured to be horizontally movable,the robot is allowed to move in both of the horizontal direction and thevertical direction. This configuration enables the robot to be movedfreely to any position within the given space.

According to another embodiment of the transporting apparatus of thepresent invention, the transporting apparatus is characterized byfurther comprising a beam for fixedly coupling top portions of the pairof upright support members while the pair of upright support members isheld in parallel. In this embodiment, the beam is used to reinforce theposition to which the upright support members.

According to a first embodiment of a transporting control method of atransporting apparatus of the present invention, the transportingcontrol method is installed in a predetermined clean environment andhaving rotating arms and end effectors, for transporting a large-sizedthin plate from a predetermined takeoff position to a processingchamber, comprising the steps of: (a) based on position data of accessedposition of the rotating arms and the end effectors, calculating amoving amount in a horizontal direction, a moving amount in a verticaldirection and driving data of the rotating arms and the end effectors;(b) moving a robot based on the moving amount in the horizontaldirection and the moving amount in the vertical direction and drivingthe rotating arms and the end effectors based on the driving data; (c)reading from storing means deflection data of the rotating arms and theend effectors which are extended; (d) calculating compensation data forcompensating a deflected amount based on the deflection data; and (e)controlling to adjust the moving amount in the vertical direction basedon the compensation data thereby to compensate the deflected amount.

According to another embodiment of the transporting control method ofthe present invention, the transporting control method is characterizedin that the step (e) is replaced with the step (f) of adjusting a tiltangle of the robot based on the compensation data thereby to compensatethe deflected amount. In this embodiment, deflection is compensated intransporting by adjusting the height of the robot.

According to another embodiment of the transporting control method ofthe present invention, the transporting control method is characterizedin that the step (e) is replaced with the step (g) of adjusting themoving amount in the vertical direction and/or the tilt angle of therobot based on the compensation data thereby to compensate the deflectedamount. In this embodiment, deflection is compensated by changing thetilt angle of the robot thereby to change the positions of the endeffectors.

According to another embodiment of the transporting control method ofthe present invention, the transporting control method is characterizedin that the deflection data read in the step (c) includes deflectiondata at a plurality of moving points of the rotating arms and the endeffectors and the compensation data calculated in the step (d) includescompensation data at each of the moving points. In this embodiment,deflection is compensated by adjusting the height and/or the tilt angleof the robot.

According to another embodiment of the transporting control method ofthe present invention, the transporting control method is characterizedin that in the step (c), the deflection data read from the storing meansdepends on whether the thin plate is held or not. In this embodiment,deflection compensation data varies depending on whether the endeffectors hold the thin plate or not.

According to another embodiment of the transporting control method ofthe present invention, the transporting control method is characterizedin that in the step (c), read from the storing means is the compensationdata calculated and stored in advance based on the deflected amount;calculating of the compensation data in the step (d) is not performed;and processing in the step (e) is performed based on the readcompensation data. In this embodiment, deflection is compensated bycalculating in advance compensation data of a deflected amountcorresponding to each of the moving positions and reading out thecompensation data. Accordingly, it becomes possible to eliminate thenecessity to calculate compensation data in moving operation, therebyreducing the load on the controller and increasing the processing speed.

According to another embodiment of the transporting control method ofthe present invention, the transporting control method is characterizedby further comprising the steps of: (h) detecting a placing position ofthe thin plate held by the end effectors; (i) comparing the placingposition and a predetermined reference placing position to calculate adisplaced amount; and (j) performing operational control to compensatethe displaced amount.

According to another embodiment of the transporting control method ofthe present invention, the transporting control method is characterizedin that the displaced amount in the step (i) includes a displaced amountin an X axis direction, a displaced amount in a Y axis direction and adisplaced amount in a rotational axis direction from the referenceplacing position, and the operational control in the step (j) isperformed to compensate each of the displaced amounts in the step (i).

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a plane view illustrating a sheet manufacturing systemcomprising a transporting apparatus according to an embodiment of thepresent invention;

FIG. 2 is a perspective view of the transporting apparatus 10 shown inFIG. 1;

FIG. 3 is a cross sectional view seen from the line A-A′ of FIG. 1;

FIG. 4A is a side view illustrating an example of lifting mechanism oftowers (upright support members);

FIG. 4B is a cross sectional view seen from the line B-B′ of FIG. 4A;

FIG. 5 is a side view of a transporting apparatus illustrating anotherexample of lifting mechanism provided at the towers;

FIG. 6 shows the operating range (direction) of the robot and its endeffectors;

FIG. 7A is a side view showing an example of tilt adjusting means;

FIG. 7B is a side view showing an example of tilt adjusting means;

FIG. 7C is a side view showing an example of tilt adjusting means;

FIG. 8 is a side view showing tilt adjusting means according anotherembodiment;

FIG. 9 is a pattern diagrams illustrating concept of tilt adjustingmeans according another embodiment;

FIG. 10A is a graph of a deflection curve line D showing deflectedamounts obtained when a measurement point (reference point) on the endeffector moves from the measurement point A to the measurement point Jduring the rotating arms being extended;

FIG. 10B is a graph showing a deflection curve line and an interpolationcurve line for compensating the deflection;

FIG. 11 is a functional block diagram illustrating transporting controlmeans for controlling transporting in the horizontal direction andvertical direction according to an embodiment of the present invention;

FIG. 12A is a view illustrating maximum transporting distance of the endeffectors 17 by rotating arms;

FIG. 12B illustrates end effectors 17 being inserted into apredetermined storage when deflected amount is not compensated;

FIG. 12C illustrates deflected amount being compensated by tiltadjusting portion;

FIG. 13 is a plain view illustrating a transporting position of thinplate by a robot;

FIG. 14 is a perspective view showing a transporting apparatuscomprising placing position detecting means according to an embodimentof the present invention;

FIG. 15 is a view illustrating a placing position (teaching position) atwhich the end effectors hold a glass plate in a X-Y plan (horizontalplane) having a pivot center of the robot as original point;

FIG. 16 is a diagram illustrating displacement in the X axis directionof the placing position from the teaching position;

FIG. 17 is a diagram illustrating displacement in the Y axis directionof the placing position from the teaching position;

FIG. 18 is a diagram illustrating relationship between the teachingposition and the placing position when the placing position is displacedfrom the teaching position in the X axis direction, the Y axisdirection, parallel direction and the rotational direction;

FIG. 19 illustrates the state shown in FIG. 18 being rotated by theangle a toward the teaching direction;

FIG. 20 is a view illustrating the teaching position where two positiondetecting sensors;

FIG. 21 is a view explaining a manner of calculating a displacement inthe rotational direction from the teaching position by measured value bythe two position detecting sensors; and

FIG. 22 is a partial perspective view for explaining an embodiment forpreventing dust pollution in the clean environment.

DESCRIPTION OF THE SYMBOLS

-   10 transporting apparatus-   11 moving table-   12 tower (upright support member)-   13 horizontal support table-   14 transporting robot-   16 rotating arm-   17 end effector-   27 lifting motor-   30 tilt mechanism (tilt adjusting means)-   40 base table-   41 moving table-   42 rail-   50 stage-   60 processing chamber-   77 vertical driving means-   80 exhaust pipe-   81 a to 81 f rotational axis-   82 a to 82 e exhaust duct-   110 position detecting sensor

BEST MODE FOR CARRYING OUT THE INVENTION

With reference to the attached drawings, embodiments for carrying outthe present invention will be described in detail below. The followingdescription deals with the case for transporting a glass plate of about2 m square as a thin plate. As a transporting apparatus of the presentinvention is an apparatus for transporting a sheet member used inmanufacturing a semiconductor integrated circuit, the transportingapparatus is operated in an environment of certain cleanness which islower than that of clean room. Accordingly, the transporting apparatusof the present invention is a transporting apparatus which meetspredetermined requirements for operating in the clean environment, forexample, prevention of dust from occurring, and is completely differentin behavior from transporting apparatus including a normal crane vehicleand a lifting machine in a storage warehouse.

FIG. 1 is a plane view illustrating a sheet manufacturing system forsemiconductor integrated circuits, having a transporting apparatusaccording to an embodiment of the present invention. The sheetmanufacturing system includes a transporting apparatus 10, a stage 50arranged in front of the transporting apparatus 10, and a processingchamber 60 arranged behind the same.

FIG. 2 is a perspective view of a transporting apparatus according toanother embodiment of the present invention, in which only aconfiguration of the horizontal support table is different from that ofthe transporting apparatus 10 in FIGS. 1 and 3. FIG. 3 is a crosssectional view seen from the line A-A′ in FIG. 1. Mounted on the stage50 are a cassette 51 having a glass plate 53and an empty cassette 52.

The transporting apparatus 10 takes out a glass plate 53 from thecassette 51 (FIG. 3) and transfers it to the rear processing chamber 60,in which the glass plate is subjected to processing in accordance with agiven purpose. The treated glass plate 53 is taken out by thetransporting apparatus 10 and transported into the empty cassette 52.The cassettes 51 and 52 are transported by an AGV (Automotive GroundVehicle) or the like and arranged on a given position of the stage ortransported out thereof.

The transporting apparatus 10 includes a base table 40, a pair ofupright towers (upright support members) 12, a horizontal support table13 supported liftably by the pair of towers 12, and a robot 14 placedand fixed onto the horizontal support member 13. The base table 40includes three rails 42 extending right and left, and a movable table 11provided movable right and left (in the direction of X axis) on therails 42.

The pair of towers 12 is provided on the moving table 41 andhorizontally movable in the right and left direction (in the directionof X). The spacing of the pair of towers 12 is small enough for the thinplate to pass between the pair of towers and the height of the towers isdetermined depending on the height of a cassette for receiving atransferred glass plate and the height of the plate processing chamber.In addition, the pair of towers 12 is preferably coupled and reinforcedby a beam at the top thereof to form like a gate.

The horizontal support table 13 is mounted on the pair of towers 12. Thehorizontal support table 13 is cantilevered by the pair of towers 12 soas to protrude toward the processing chamber 60 and is liftable alongthe pair of towers 12. The horizontal face of the horizontal supporttable 13 used as a table is as small as possible, and is preferably inthe shape of “minoko type plate” (curved plate) or perforated plate.Since dust attached to a thin plate to be transported reduces a yield(good item rate) and therefore, the thin plate requires a manufacturingenvironment of high cleanness, it is preferably to reduce as much aspossible disturbance of air during lifting so as to prevent disturbancein the environment of the factory.

Placed and fixed onto the horizontal support table 13 is a robot 14. Therobot 14 has two rotating arms 16 which are rotatable around joints.Each of the rotating arms 16 has at an end thereof an end effector 17for transporting a glass plate 53.

When the glass plate 53 is taken out of the cassette 51, the movingtable 41 to which the pair of towers 12 is fixed is moved in thehorizontal direction (x axis direction), the horizontal support table 13is moved up and down (in the Z axis direction) to adjust the height, andthereby, the robot 14 is moved in front of the cassette 51 in which theglass plate is received. When the glass plate 53 is taken out of thecassette 51, the rotating arms 16 are driven to insert the end effectors17 into the cassette 51, then, the horizontal support table 13 is movedup by predetermined height (slightly) and thereby the glass plate 53 istaken up.

Then, the end effectors 17 are drawn close to the body of the robot 14(in the Y axis direction), the robot 14 is rotated by 180°, and themoving table 41 and the horizontal support table 13 are moved in the Xand Z axes directions, respectively, to be stopped in front of theprocessing chamber 60. Then, the gate 61 is opened to extend the arms 16so as to insert the end effectors 17 into the processing chamber 60 andplace the glass plate 53 on. After processing on the glass place 53 isfinished, the end effectors 17 are used to take the glass plate out ofthe processing chamber 60 and store it in the other cassette 52.

The robot having rotating arms used in the present invention includes ascalar type robot having horizontally turning arms and a multijoint typerobot having joints rotating in the vertical plane or around an axis inthe arm direction. The robot placed on the horizontal support table 13may be configured to have a lifting mechanism on itself for fineadjustment in the vertical direction. Provision of the robot itself witha lifting mechanism presents an advantage that fine adjustment in the Zaxis direction becomes possible. However, it also presents problems thatthe robot configuration becomes complicated and the upward load on thehorizontal support table is increased due to increase in weight.

The robot also used in the present invention has the end effectors 17for placing a thin plate, which end effectors 17 each can be providedwith an absorbing mechanism. The shape of the absorbing mechanism may bepublicly well-known. Further, the joint is subjected to sealing bymagnetic fluid and all the coupling portions are preferably configuredto prevent dust in the robot from coming out of the robot by use ofpacking.

As described above, the pair of towers 12 has the horizontal supporttable 13, on which the robot 14 is placed and the horizontal supporttable 13 is moved in the up and down direction (Z axis direction). Thepair of towers 12 is fixed to the moving table 41 to be moved in thehorizontal direction (X axis direction). Further, the horizontal supporttable 13 includes a tilt mechanism (tilt adjusting means) 30 (FIG. 3),and the robot 14 is arranged via the tilt adjusting means. The followingdescription is made about means for moving in the X axis direction,moving means in the Z axis direction and tilt adjusting means of thetransporting apparatus according to an embodiment of the presentinvention.

(Means for Moving in the X Axis Direction)

With use of FIGS. 1 and 3, the configuration of the base table 40 andmotion in the X axis direction of the pair of towers 12 fixed to thebase table 40 are described. The base table 40 is provided with a movingtable 41 slidable on three rails 42, and fixed onto the moving table 41is the pair of towers 12. On the moving table 41 a motor 19 is fixed,and a pinion attached to the motor 19 and a rack attached to the rail 42enable movement in the X axis direction. The motor 19, the rack andpinion may be attached to either of the rails 42, and preferably to thecenter one of the rails 42.

This horizontally moving mechanism adopted here includes a system ofhorizontally parallel rails and rack-and-pinion, a cableway system, aball screw rail system, a rail running system, an air-cushion system, amagnetic levitation system and other well-known heavy lifting systems. Adriving source of such a horizontally moving mechanism used hereincludes a servo motor, a stepping motor, a linear motor, a fluidpressure cylinder of hydraulic pressure or air pressure and otherwell-known driving sources.

(Means for Moving in the Z Axis Direction)

The pair of towers 12 has at least a function of supporting thehorizontal support table 13 on which the robot 14 is arranged and afunction of moving the horizontal support table 13 in the up and downdirection (Z axis direction). Driving in the up and down direction isperformed by a guide portion for assuring accurate motion in the up anddown direction and a lift driving portion. An example of the specificmechanism is described with use of FIGS. 4A and 4B.

FIG. 4A is a lateral view showing an example of the lifting mechanismprovided on the towers (upright support members) 12. FIG. 4B is across-sectional view seen from the line B-B′ shown in FIG. 4A. In FIG.4A, the lifting motor 27 rotates a coupling axis 26 via a bevel wheel.The coupling axis 26 rotates a pole type screw 25 provided in each ofthe pair of the towers 12 via a bevel wheel provided at the bottom ofeach of the towers 12.

The screw 25 is engaged with a screw bearing 28 fixed to the horizontalsupport table 13. When the screw 25 rotates, the screw bearing 28 movesup and down in accordance with the rotation direction of the screw 25.Accordingly, rotation of the screw 25, via the screw bearing 28, causesthe horizontal support table 13 to move up and down along acorresponding linear guide 24. Since as described above, the robot isplaced on the horizontal support table 13, the height of the rotatingarms 16 and end effectors 17 of the robot 14 can be adjusted in the Zdirection. The horizontal support table 13 is movable from the highest Hto the lowest L.

Here, the guide portion used here includes a bearing, a roller and guidemechanism for arranging a rotary member such as a roller along areference rail, a contact guide mechanism making use of magneticrepulsive force or air film, and the like. The lifting mechanism usedhere may be a ball screw, a rack and pinion, a pulley, suspending ribbonand balance bell, rod or rodless air balance cylinder, any type orbrakes and other well-known driving portions.

(Other Examples of Means for Moving in the Z Axis Direction)

FIG. 5 is a lateral view of a transporting apparatus illustratinganother example of a lifting mechanism provided at the pair of towers12. This lifting mechanism has an air balance cylinder 34 in order tominimize energy. Around a motor provided at the bottom of the tower 12and a sprocket 32 provided close to the top of the tower 12, a ringchain 33 is hung. To the left of the chain 33, the air balance cylinder34 is arranged. The horizontal support table 13 moving as guided by thelinear guide 24 and the chuck of the air balance cylinder 34 are coupledto the chain 33 and air pressure corresponding to the weight of thehorizontal support table 13 with the robot 14 placed on is applied tothe cylinder 34. The horizontal support table 13 is movable from thelowest position L to the highest position H.

(Movable Range by Robot 14)

FIG. 6 shows an operating range of the robot 14 and end effectors 17.The pair of rotating arms 16 and the end effectors 17 provided at therespective ends thereof are accessible to the processing chamber 60arranged within a sector range of approximately 2200 to the right sideof the pair of towers 12 in FIG. 6. To the left side of the pair oftowers 12 in FIG. 6, once the robot 14 is turned, the end effectors 17become accessible to the cassettes 51 and 52 between the pair of towers12. If the two end effectors 17 are operated simultaneously, thetransporting speed of a sheet can be doubled.

(Tilt Adjusting Means)

As shown in FIG. 3, the horizontal support table 13 has a tilt mechanism(tilt adjusting means) 30, and the robot 14 is arranged on thehorizontal support table 13 via the tilt adjusting means. The tiltadjusting means is provided for adjusting the tilt angle of the robot 14within an angle “T”. FIGS. 7A through 7C are lateral views illustratingexamples of the tilt adjusting means 30.

The tilt adjusting means 30 includes a tilt table 31 attached pivotableto a hinge portion 35 fixed to the horizontal support table 13 and atilt driving mechanism. The tilt driving mechanism includes a pole-typescrew 36, a bearing screw 37 engaged with the screw 36, a rotationdriving portion 45 for rotating and counterrotating the screw 36 and abearing 46.

When the rotation driving portion 45 rotates the screw 36, the bearingscrew 37 moves left or right in accordance with the rotating directionof the screw 36. The bearing screw 37 has a sliding hinge 38 attachedthereto and the sliding hinge moves along a sliding guide 39. This movesa left end of the tilt table 31 upward and downward and thereby theangle of the upper face of the tilt table 31 becomes changed. Since therobot 14 is fixed to the upper face of the tilt table 31, the horizontaltilt of the robot 14 is changed following the angle change of the tilttable 31.

FIG. 7B shows angle change when the screw 36 with a clockwise rotatingscrew is rotated clockwise. When the screw 36 rotates clockwise, thebearing screw 37 moves in the left direction and the left end of thetilt table 31 moves downward. FIG. 7C shows angle change when the screw36 is rotated counterclockwise. When the screw 36 rotatescounterclockwise, the bearing screw 37 moves in the right direction andthe left end of the tilt table 31 moves upward.

(Other Examples of Tilt Adjusting Means)

FIG. 8 illustrates another example of the tilt adjusting means. In thisexample, the angle of a tilt table 71 coupled pivotable to a hingeportion 72 changes by driving a cam 73.

Further, FIG. 9 illustrates another example of the tilt adjusting means.In this example, the tilt angle can be changed 360° in the horizontalplane. The tilt table 76 is supported by three parts composed of a fixedposition rotational axis 79, and vertical driving means 77 and 78. Thefixed position rotational axis 79 is fixed in position and is rotatable360° in the horizontal direction and 90° in the vertical direction. Thevertical driving means 77 and 78 have driving means 77 a and 78 b of oilpressure or the like and driving axes 77 b and 78 b, which move upwardand downward the tilt table 76 by the driving means 77 a and 78 a. Inthis configuration, end portions 77 c and 78 c of the driving axes 77 band 78 b move the tilt table 76 upward and downward. The fixed positionrotational axis 79 is fixed at the upper and lower positions, the twopoints are freely movable upward and downward, which allows tilt to becontrolled 360° in the horizontal direction including back and forth andaround directions.

(Deflection Compensation)

A transporting apparatus according to the present invention transports alarge-size thin plate. Then, the robot 14 becomes large sized and therotating arms become weighted. When the rotating arms are extended, thecenters of the end effectors can be extended 4,000 mm or more from thecenter of the robot. The self-weight of the rotating arms and the weightof the thin plate deflect the rotating arms which makes the edges of theend effectors lowered from the original positions. This sometimes makesit difficult to take the thin plate out of a predetermined positioninside the cassette precisely and to place it on the accurate position.Accordingly, in order to transport the thin plate accurately and safely,it is preferable to compensate the distortion.

FIG. 10A is a graph of a deflection curve D showing deflected amountswhen a measurement point (reference point) on the end effector moves ameasurement point A to a measurement point J in extending the rotatingarm. The straight line S in the graph shows a movement trace with nodeflection and a deflection curve D shows that a deflected amount is 0at the point A and continues to be increased to be a maximal deflectedamount d at the point J.

In another embodiment of the present invention, in order to transport athin plate to a target plate accurately and safely, this deflection iscontrolled to be compensated. Deflection control is performed to cancelthe deflection shown in FIG. 10A. More specifically, the horizontalsupport table 13 is moved upward in such a manner that the movementtraces a line in line symmetry with the curved line with respect to thestraight line S as shown in FIG. 10A so as to cancel the deflectionthereby compensating the deflection in the Z axis direction.

However, the graph of FIG. 10A is only a line chart plotted withdeflected amounts at measurement points A to J. Therefore, a differencefrom an actual deflected amount at each of the measurement points islikely to cause a trouble of oscillating in the vertical motion. Then,interpolation control is performed to make the line chart match thecurved line, which is used as a basis to perform compensation. Thissmoothes extending operation of the rotating arms. The interpolationcontrol is performed for example in a method of performing at eachmeasurement point the operation of calculating the radius of a circleincluding deflected amounts at three adjacent points. This operationexecuted allows a curved line analogous to the line chart to beobtained. In this way, a smooth curved line C shown in FIG. 10B can beobtained, and by driving in the Z axis direction based on this curvedline, smooth compensated is allowed to be performed.

(Transporting Driving Control)

FIG. 11 is a functional block diagram of transporting control meansaccording one embodiment of the present invention. A transportingcontroller 120 accesses the thin plate and controls motion in thehorizontal direction (X axis direction), motion in the verticaldirection (Z axis direction), tilt angle of the robot 14, rotation ofthe robot 14 and the operation of rotating arms 16 in order to transportthe thin plate to a target position. Motion in the Z axis direction isperformed by lift driving means 121, while motion in the X axisdirection is performed by horizontally moving means 130. Thisconfiguration enables the robot 14 as a whole to be transported to apredetermined position.

Robot controlling means 135 controls rotation of the robot and theoperation of the rotating arms. Further, the tilt adjusting means 125 isused to adjust the tilt angle of the horizontal support table 13. Eachmoving mechanism and each part of the robot are provided with varioussensors 138, and a detected signal is fed back to the transportingcontroller 120.

When the transporting controller 120 receives transporting control datasuch as position data indicating a location where a thin plate existsand a transporting position, the transporting controller 120 calculatesa moving direction and a moving amount from the data of the currentposition and the received position data. The calculated movement amountdata is divided into horizontal direction data and vertical directiondata, which are output to respective driving control means. The movingamount data in the X axis direction is output to the horizontallydriving controller 131 and is used as a basis to drive a horizontallydriving portion 132. The moving amount data in the Z axis direction isoutput to the vertical driving controller 122 of the lift driving means121 and is used as a basis to drive a lift driving portion 123. Therobot 14 moves to a predetermined position in the X axis direction andin the Z axis direction.

The robot controller 136 drives an arm driving portion 137 based on thedata from the transporting controller 120 to operate the rotating arms16 and the horizontally rotating operation.

The transporting controller 120 shown in FIG. 11 further includesdeflection compensating means 140. The deflection compensating means 140receives current position information of the robot 14 and operationalposition information of the rotating arms from the transportingcontroller 120 to adjust the height of the edge of each of the endeffectors 17 for deflection compensation. The deflection compensatingmeans 140 includes a compensation information calculating portion 141for calculating a compensation amount for compensating deflection and adeflection information storing portion 143 for storing deflection dataof each measurement point when the rotating arms 16 are extended. Thecompensation information calculating portion 141 reads a deflectedamount (compensation amount) measured in advance from the deflectioninformation storing portion 143 in accordance with the received positioninformation and the like and calculates data to be compensated.

The calculated compensation data is output to the lift driving means 121or the tilt driving controller 126. The vertical position of thehorizontal support table 13 or the tilt angle of the robot 14 is changedthereby to compensate the deflected amounts. Driving of the horizontalsupport table 13 and change of the tilt angle of the robot 14 may beboth performed thereby compensating the distortion more accurately.

An example of compensating a deflected amount by use of a tilt adjustingportion is described specifically with reference to FIGS. 12A to 12C.FIG. 12A is a view illustrating a maximal transfer distance of the endeffectors 17 by the rotating arms 16. The maximal transfer distance ofthe rotating arms 16 is a distance (m) from a state 100 where the endeffectors 17 are held close to the center of the robot to a state 101where the rotating arms 16 are extended to draw out the end effectors 17further. As the transfer distance becomes further, the deflection of therotating arms 16 becomes larger.

FIG. 12B is a view illustrating a case of inserting the end effectors 17into a predetermined cassette 51 when deflection is not compensated. Inthis case, if the rotating arms 16 are only driven to extend the endeffectors 17 straight in the horizontal direction, the end effectors 17are likely to hit the cassette 51.

FIG. 12C is a view illustrating a case where the tilt adjusting portion30 is used to compensate deflection. When the tilt adjusting portion 30is used to increase the tilt angle slightly, the rotating arms 16extends while keeping a predetermined tilt angle thereby to raising theposition of the end effectors 17, which enables the end effectors 17 tobe prevented from hitting the cassette 51.

(Operation Checking Experiments)

A transporting apparatus of shape shown in FIGS. 2, 4 and 13 wasmanufactured with the following specifications and operated actually foroperation check. FIG. 13 is a plain view for illustrating a transportingposition of a thin plate by the robot 14. The robot 14 is, as shown inFIG. 5, capable of transporting the plate horizontally within 220° andprocessing chambers are provided in four directions, respectively, foroperation check.

The towers 2 are 4,250 mm in height, 3,820 mm in width between the towerouter walls, 2,620 mm in width between the tower inner walls and 600mm×500 mm in tower width, and the corners to the robot side of towersare cut off.

Three rails are prepared (distance between the rails 830 mm and 2,000mm), each is of 6,500 mm in length, the rail width 33 mm×the height ofthe rail upper surface is 220, the shelf portion 3 is tower side liftingbeam is 2,700 mm, having a bottom of 400 mm in width and 1,800 mm inlength.

The robot 4 is a double arm robot with common first arm (boomerang-typerobot), and the main body of the robot is arranged at the center of theshelf portion 1400 mm far from the center of the towers. The height ofthe robot is 880 mm, the diameter of the robot body is 800 mm, thelength of the arm is 1,625 mm in minimal rotational radius (1,450 mm indistance between centers of joints) and the first arm open degree is130°. The end effectors are operated linearly by a pulley and beltprovided at the arm joints from the robot center axis.

The tilt mechanism has the following specifications: two worm-gearmotors are arranged 60° rightward and leftward relative to the lineperpendicular to the rails from the robot center, tilting is set freely360°, and maximal tilt angle (tilt adjusting angle) is ±20.

Each of the end effectors is 2,310 mm in length, 1,260 mm in width offinger portion (60 mm×4 finger portions)×1,800 mm in length.

The capacity of this transporting apparatus is 1,100-3,600 mm intransporting-allowed lifting range, 2,500 mm/3.5 seconds in liftingtime, and 2,500 mm in horizontally moving distance. The rotational angleof the robot is 500°, rotational speed is 180 degree/2 seconds and tiltspeed ±2°/second. As shown in FIG. 6, the maximal transporting distanceof one arm of the robot is 4,150 mm while the center of the end effectorcan extend 4,300 mm far from the center of the robot. Its speed is 4,150mm/3 seconds. Transporting-in or transporting-out direction of the robot14 is in the four directions P, Q, R and S shown in FIG. 7. Since thetowers 12 are moved by the horizontally moving mechanism 5 having rails,the transporting destination can be freely set as far as thehorizontally moving distance is within 2,730 mm.

This transporting apparatus is used to transport a glass plate of 0.7 mmin thickness×2,000 mm in width×2,200 mm in length from the cassette 51(2,200 mm in width×2,400 mm in depth×1,600 mm in height, 1,200 mm inheight of the bottom stage and 2,720 mm in height of the top stage) to atemporal table in the processing chamber 60 of 1,600 mm in height. Afterprocessing, the gate 61 is opened, the robot 14 of the present inventiontakes out the glass plate 8 and stores it into the cassette 52. Althoughonly one horizontal support table 13 is provided in the descriptionabove, there can be provided a plurality of horizontal support tables 13each of which a robot can be placed on.

(Calculation and Compensation of Displacement of Thin Plate PlacingPosition)

Further, the transporting apparatus of the present invention may beprovided with the following placing position detecting means. First, asshown in FIG. 13, a thin plate detectable position detecting sensor 110is provided at a predetermined position in the transporting apparatus.When the end effectors hold the thin plate by adsorption, they transportthe thin plate in such a manner that adjacent two sides of the heldplate follow a given circular arc which passes over the positiondetecting sensor 110. Then, the timing of detection by the sensor andthe size and shape of the thin plate known in advance are used todetermine whether the thin plate is held properly by the end effectors.

With this configuration, positional displacement of the thin plate onthe end effectors is detected and for example, controlling means can beused to detect the positional displacement. In other words, the presetteaching position and the actual position are compared to calculatedisplacement. Here, calculated are distance and angle. However,calculation of displaced angle requires using of a plurality of sensorsor plural times of detection by one sensor to obtain necessary positioninformation.

This method is advantageous in that it is possible to judge whether ornot the thin plate is held properly by making the plate pass over the atleast one position detecting sensor 110 only once. If this transportingfor judgment is included into normal transporting, the judgment can beperformed more efficiently. The sensor used here includes a line sensorand a spot sensor, and a known optical noncontact sensor is preferablyused.

FIGS. 14 to 21 are used to explain in detail an apparatus and method fordetecting the placing position of the thin plate by the end effectorsand compensating displacement of the placing position. In the followingexample, a glass plate is transported as the thin plate.

FIG. 14 is a perspective view illustrating an example of a transportingapparatus provided with placing position detecting means of the presentinvention. FIGS. 15 to 21 are views for explaining analysis of the glassplate placing position by the end effectors in the X-Y plane (horizontalplane) where the rotational axis of the robot is the original point.

The transporting apparatus as shown in FIG. 14 is provided with theplacing position detecting means. The placing position detecting meansincludes a position detecting sensor provided on the horizontal supporttable 13 and a position calculating portion for calculating displacementof the thin plate held by the end effectors 17 based on a detectedsignal from the position detecting sensor. The position calculatingportion is capable of calculating by a conventional microprocessorconsisting of a CPU, other logic circuits, memory and control program(including operational program). As such calculating by themicroprocessor is well known, further description about theconfiguration of the microprocessor is omitted here. Description about acalculating manner is given later.

The position detecting sensor has a light emitting portion and a lightreceiving portion opposed to each other at horizontally projectedportions which are spaced apart vertically. The position detectingsensor detects presence of a blocking object by judging whether lightfrom the light emitting portion is received by the light receivingportion or not(the optical path from the light emitting portion to thelight receiving portion is blocked or not). Accordingly, if thetransporting path used when the glass plate taken out of the cassette istransported to the processing chamber or when the glass plate isreturned back from the processing chamber to the cassette by the endeffectors is set in such a manner that at least one side of the glassplate crosses the optical path of the position detecting sensor, theposition detecting means is allowed to detect the position of the glassplate on the end effectors.

(Glass Plate Position Measuring Method by Placing Position DetectingMeans)

As shown in FIG. 13, the robot 14 is capable of transporting the glassplate taken from the cassette 51 to the processing chamber 60 which iswithin the angle of 180° in the opposite direction to the cassette 51.In FIG. 13, as one example, there are provided processing chambers 60 inthree directions. When the robot 14 takes the glass plate out of thecassette 51, the glass plate is transported in such a manner that atleast one side of the glass plate follows a given path crossing theoptical path of the position detecting sensor 110. FIGS. 15 to 21 show adetected glass plate when the glass plate is held by the end effectorsand the robot 14 is rotated in the horizontal direction at a givenreference position. In these figures, the X-Y plane is shown in whichthe rotational axis of the robot is set as an original point and theinitial position O (r, 0) is given on the X axis.

The placing position detecting means is capable of obtaining theposition of the glass plate from the position information of the endeffectors by a controller of the robot and detection information of theglass plate detected by the position detecting sensor to calculatedisplacement of the measurement position from the teaching position. Theposition detecting means measures operational angles of the robotobtained when the robot is rotated from the initial position O (r, 0) tothe positions detected by the sensor of the placing position detectingmeans, such as the position P1 (XP1, YP1) on the edge of the glassplate, the positions P2 (XP2, YP2) and P3 (XP3, YP3) on one sidecrossing the side including P1 at right angles, and the position P4(XP4, YP4) on one side crossing the side including P2 and P3 at rightangles (the angles are hereinafter referred to as “measurement anglesθP1, θP2, θP3 and θP4“) (See FIGS. 16 to 19).

The measurement results are transferred to and stored in storing means.These stored measurement results and the teaching position stored inadvance in the storing means are transferred to the calculating meanswhen necessary to calculate displacement. If the position information isdetected much in variety and amount, it becomes possible to detectdisplacement in the direction (X axis direction in the figures)perpendicular to the direction (Y axis direction in the figures) inwhich the glass plate is transported or the end effectors are operatedby the robot, and displacement in the rotational direction (θ directionin the figures). The description below is made about a displaced amountcalculating method based on detected position information.

(Teaching Method of Reference Placing Position)

FIG. 15 illustrates the angle and position (hereinafter referred to as“teaching position”) of each side of the glass plate detected by theposition detect sensor 110 when the end effectors hold the glass plateat the preset reference position. When the glass plate is held at thereference position and the end effectors are moved to an initialposition, the robot 14 is turned to measure the angle θQ1 from theinitial position to the position for detecting the edge of the glassplate. This result is stored in the storing means as a teaching angleθQ1. This information is used as a basis to calculate a teachingposition Q1 (XQ1, YQ1) by the calculating means. An equation forcalculating this teaching position Q1 (XQ1, YQ1) is given as follows. Inthe equation, r is a distance from the rotational center of the robot tothe optical axis of the sensor. $\begin{matrix}{\begin{pmatrix}X_{Q\quad 1} \\Y_{Q\quad 1}\end{pmatrix} = {\begin{pmatrix}{{Cos}\quad\theta_{Q\quad 1}} & {{- {Sin}}\quad\theta_{Q\quad 1}} \\{{Sin}\quad\theta_{Q\quad 1}} & {{Cos}\quad\theta_{Q\quad 1}}\end{pmatrix}\begin{pmatrix}r \\0\end{pmatrix}}} & \left( {{Equation}\quad 1} \right)\end{matrix}$From this equation, the teaching position Q1 (XQ1, YQ1) can becalculated. Further, this teaching position Q1 (XQ1, YQ1) may not bemeasured value but desired coordinates set in advance in the storingmeans.

The angles of Q2, Q3 and Q4 are measured in the same way to calculateteaching positions.

(Calculating Method of Displacement in the X Axis Direction)

A calculating method of displacement in the X axis direction isdescribed with reference to FIG. 16 in which the solid line shows anactual placing position and the broken line shows the teaching position.In FIG. 16, the glass plate on the end effectors is displaced in the Xaxis normal direction from the teaching position. The sensor isrelatively turned to measure an operating angle of the robot(hereinafter referred to as “measurement angle θP1”) from the initialposition to the position P1 (XP1, YP1) where the glass plate crosses theoptical axis. As is the case with the teaching angle, the glass plateposition P1 (XP1, YP1) is calculated as follows. $\begin{matrix}{\begin{pmatrix}X_{P\quad 1} \\Y_{P\quad 1}\end{pmatrix} = {\begin{pmatrix}{{Cos}\quad\theta_{P\quad 1}} & {{- {Sin}}\quad\theta_{P\quad 1}} \\{{Sin}\quad\theta_{P\quad 1}} & {{Cos}\quad\theta_{P\quad 1}}\end{pmatrix}\begin{pmatrix}r \\0\end{pmatrix}}} & \left( {{Equation}\quad 2} \right)\end{matrix}$

This result is used to calculate a displaced amount (ΔXP1, ΔYP1).$\begin{matrix}{\begin{pmatrix}{\Delta\quad X_{P\quad 1}} \\{\Delta\quad Y_{P\quad 1}}\end{pmatrix} = {\begin{pmatrix}X_{P\quad 1} \\Y_{P\quad 1}\end{pmatrix} - \begin{pmatrix}X_{Q\quad 1} \\Y_{Q\quad 1}\end{pmatrix}}} & \left( {{Equation}\quad 3} \right)\end{matrix}$

From this calculation result of displacement a displaced amount in the Xaxis direction of the glass plate on the end effectors ΔXP1 (|XP1-XQ1|)is calculated.

(Calculating Method of Displacement in the Y Axis Direction)

A calculating method of a displacement in the Y axis direction isdescribed with reference to FIG. 17 in which the solid line shows anactual placing position and the broken line shows the teaching position.In FIG. 17, the glass plate on the end effectors is displaced in the Yaxis normal direction from the teaching position. As is the case withdisplacement in the X axis direction, a measurement angle θP2 of therobot from the initial position to the point P2 on a side perpendicularto the side including P1 is measured. This P2 (XP2, YP2) is used tocalculate a displaced amount in the Y axis direction as follows.$\begin{matrix}{\begin{pmatrix}X_{P\quad 2} \\Y_{P\quad 2}\end{pmatrix} = {\begin{pmatrix}{{Cos}\quad\theta_{P\quad 2}} & {{- {Sin}}\quad\theta_{P\quad 2}} \\{{Sin}\quad\theta_{P\quad 2}} & {{Cos}\quad\theta_{P\quad 2}}\end{pmatrix}\begin{pmatrix}r \\0\end{pmatrix}}} & \left( {{Equation}\quad 4} \right)\end{matrix}$When the coordinates of the teaching position Q2 are (XQ2, YQ2), adisplaced amount in the Y axis direction ΔY (ΔXP2, ΔYP2) is given asfollows. $\begin{matrix}{\begin{pmatrix}{\Delta\quad X_{P\quad 2}} \\{\Delta\quad Y_{P\quad 2}}\end{pmatrix} = {\begin{pmatrix}X_{P\quad 2} \\Y_{P\quad 2}\end{pmatrix} - \begin{pmatrix}X_{Q\quad 2} \\Y_{Q\quad 2}\end{pmatrix}}} & \left( {{Equation}\quad 5} \right)\end{matrix}$From this, a displaced amount in the Y axis direction AY is calculatedas |YP2-YQ2|.(Calculating Method of Displacement in the Rotational Direction)

The displacement calculating method when a displacement exists in therotational direction is described with reference to FIG. 18. Likewise inFIGS. 16 and 17, the solid line shows the actual placing position of theglass plate and the broken line shows the teaching position. In FIG. 18,the glass plate shown by the solid line is displaced in parallel in theX and Y axes directions, and rotational direction as compared with theglass plate at the teaching position. The method for calculating adisplacement in the rotational direction is measuring a measurementangle θP3 from the initial position to P3(XP3, YP3) on the same side asP2, in addition to the points P1 and P2 on the respective sides of theglass plate as described above to calculate the coordinates in the sameway as P1 and P2. $\begin{matrix}{\begin{pmatrix}X_{P\quad 3} \\Y_{P\quad 3}\end{pmatrix} = {\begin{pmatrix}{{Cos}\quad\theta_{P\quad 3}} & {{- {Sin}}\quad\theta_{P\quad 3}} \\{{Sin}\quad\theta_{P\quad 3}} & {{Cos}\quad\theta_{P\quad 3}}\end{pmatrix}\begin{pmatrix}r \\0\end{pmatrix}}} & \left( {{Equation}\quad 6} \right)\end{matrix}$From this equation, P3 (XP3, YP3) is calculated.

The side including this measurement point P3 (XP3, YP3) is rotationallydisplaced by a displaced amount α with respect to the side including theteaching position Q3 (XQ3, YQ3) Since the displaced amount a is an angleformed by a vector P2P3 from P2 to P3 and a vector Q2Q3 from Q2 to Q3,it is calculated as follows. $\begin{matrix}{{\overset{\longrightarrow}{P\quad 2P\quad 3} \cdot \overset{\longrightarrow}{Q\quad 2Q\quad 3}} = {{\overset{\longrightarrow}{P\quad 2P\quad 3}}{\overset{\longrightarrow}{Q\quad 2Q\quad 3}} \times {Cos}\quad\alpha}} & \left( {{Equation}\quad 7} \right) \\{\alpha = {{Cos}^{- 1}\left( \frac{\begin{matrix}{{\left( {X_{P\quad 3} - X_{P\quad 2}} \right)\left( {X_{Q\quad 3} - X_{Q\quad 2}} \right)} +} \\{\left( {Y_{P\quad 3} - Y_{P\quad 2}} \right)\left( {Y_{Q\quad 3} - Y_{Q\quad 2}} \right)}\end{matrix}}{\sqrt{\begin{matrix}{{\left( {X_{P\quad 3} - X_{P\quad 2}} \right)^{2}\left( {X_{Q\quad 3} - X_{Q\quad 2}} \right)^{2}} +} \\{\left( {Y_{P\quad 3} - Y_{P\quad 2}} \right)^{2}\left( {Y_{Q\quad 3} - Y_{Q\quad 2}} \right)^{2}}\end{matrix}}} \right)}} & \left( {{Equation}\quad 8} \right)\end{matrix}$From these equation, the displaced amount a is calculated.(Displacement Compensating Method)

When the glass plate is displaced in the X axis direction as shown inFIG. 16, the measurement position of the glass plate shown by the solidline is displaced by ΔX to the right of FIG. 16 with respect to theteaching position shown by the broken line. With the transportingapparatus of the present invention, if the glass plate is displaced fromthe shown position to the left of the figure by ΔX, the displacement canbe compensated.

The same goes for FIG. 17 where the glass plate is displaced in the Yaxis direction. Displacement is compensated by placing the glass placein an opposed direction to the displaced direction from the teachingposition.

When the glass plate is displaced in the rotational direction, the robotis rotated by the displaced amount a in the rotational direction in theexperimental glass plate coordinates of FIG. 19. The measurement pointsP1 and P2 are moved to P4 and P5, respectively. The coordinates of theseP4 and P5 are calculated by the following equations. $\begin{matrix}{\begin{pmatrix}X_{P\quad 4} \\Y_{P\quad 4}\end{pmatrix} = {\begin{pmatrix}{{Cos}\quad\alpha} & {{- {Sin}}\quad\alpha} \\{{Sin}\quad\alpha} & {{Cos}\quad\alpha}\end{pmatrix}\begin{pmatrix}X_{P\quad 1} \\Y_{P\quad 1}\end{pmatrix}}} & \left( {{Equation}\quad 9} \right) \\{\begin{pmatrix}X_{P\quad 5} \\Y_{P\quad 5}\end{pmatrix} = {\begin{pmatrix}{{Cos}\quad\alpha} & {{- {Sin}}\quad\alpha} \\{{Sin}\quad\alpha} & {{Cos}\quad\alpha}\end{pmatrix}\begin{pmatrix}X_{P\quad 2} \\Y_{P\quad 2}\end{pmatrix}}} & \left( {{Equation}\quad 10} \right)\end{matrix}$

From these equations, the coordinates of P4 (XP4, YP4) and P5 (XP5, YP5)can be calculated. However, although the rotational displacement can becompensated, the displacements in the X axis and Y axis directions arenot compensated. The displaced amounts can be calculated by comparingthe X coordinate between P4 and Q1 for the displacement in the X axisdirection and comparing the Y coordinate between P5 and Q2 for thedisplacement in the Y axis direction. These calculated displaced amountsare used to correct the teaching position of the glass plate. In thetransporting apparatus of the present invention, the displacement in theX axis direction is corrected by correcting the movable table 41, thedisplacement in the Y axis direction can be corrected by extending therotating arms 16, and the displacement in the rotational direction canbe corrected by rotation of the robot as described above.

While FIGS. 13 to 19 treat the case of one sensor provided, atransporting apparatus shown in FIG. 20 has two placing positiondetecting means (sensors). The placing position detecting means iscomprised in such a manner that the position detecting sensors areprovided at different distance from the pivot center of the robot. Asdescribed above, the position calculating portion calculates a displacedamount of the placing position of the end effectors 17. In the followingdescription, the second sensor is provided outside of the aforementionedsensor and its teaching position is indicated by the coordinates V (x,x).

<Teaching Method>

When the end effectors hold the glass plate at the preset referenceposition as mentioned above, angles and positions of sides of the glassplate detected by the position detecting sensors 110 are shown. Theglass plate is held at the predetermined reference position and the endeffectors are moved to the initial position, and then, the robot 14 isrotated to measure angles θQ1, θV1 from the initial position to thepositions where the edges of the glass plate are detected.

These results are stored in storing means as the teaching angles θQ1,θV1. This information is used as a basis to calculate teaching positionsQ1 (XQ1, YQ1), V1 (XV1, YV1) by the calculating means. The equation forcalculating the teaching position Q1 (XQ1, YQ1) is the same as theaforementioned equation (2), and the equation for calculating V1(XV1,YV1) is as mentioned below. In the equation, r1 and r2 are distancesfrom the rotational center of the robot to the optical axes of thesensors. $\begin{matrix}{\begin{pmatrix}X_{Q\quad 1} \\Y_{Q\quad 1}\end{pmatrix} = {\begin{pmatrix}{{Cos}\quad\theta_{Q\quad 1}} & {{- {Sin}}\quad\theta_{Q\quad 1}} \\{{Sin}\quad\theta_{Q\quad 1}} & {{Cos}\quad\theta_{Q\quad 1}}\end{pmatrix}\begin{pmatrix}r_{1} \\0\end{pmatrix}}} & \left( {{Equation}\quad 11} \right) \\{\begin{pmatrix}X_{V\quad 1} \\Y_{V\quad 1}\end{pmatrix} = {\begin{pmatrix}{{Cos}\quad\theta_{V\quad 1}} & {{- {Sin}}\quad\theta_{V1}} \\{{Sin}\quad\theta_{V\quad 1}} & {{Cos}\quad\theta_{V1}}\end{pmatrix}\begin{pmatrix}r_{2} \\0\end{pmatrix}}} & \left( {{Equation}\quad 12} \right)\end{matrix}$From these equations, the teaching positions Q1(XQ1, YQ1) and V1(XV1,YV1) are calculated. Further, these teaching positions are notmeasurement values but can be desired coordinates preset in the storingmeans.

Likewise, the angles of Q2, Q3, Q4, V1, V2, V3 and V4 are measured tocalculate the teaching position. Displacement in the X axis directioncan be calculated by each sensor as described above.

Then, FIG. 21 is utilized to explain a method of calculatingdisplacement in the rotational direction from the teaching positionbased on the measurement value when two sensors are provided. In thefigure, the solid line shows an actual placing position of the glassplate and the broken line shows the teaching position. In FIG. 21, thecenter of the glass plate is displaced from the teaching position to thecoordinates U and further, the glass plate placed on the end effectorsis displaced in the counterclockwise direction around the center of thecoordinates U. Each of the sensors is rotated relatively to measure theoperating angles of the robot (hereinafter referred to as “θP1, θW1”)from the initial position to the positions P1 (XP1, YP1), W1 (XW1, YW1)where the glass plate crosses the optical axes. As is the same with theaforementioned teaching angle, the measurement point P1 (XP1, YP1), W1(XW1, YW1) of the glass plate is calculated as follows. $\begin{matrix}{\begin{pmatrix}X_{P\quad 1} \\Y_{P\quad 1}\end{pmatrix} = {\begin{pmatrix}{{Cos}\quad\theta_{P\quad 1}} & {{- {Sin}}\quad\theta_{P\quad 1}} \\{{Sin}\quad\theta_{P\quad 1}} & {{Cos}\quad\theta_{P\quad 1}}\end{pmatrix}\begin{pmatrix}r_{1} \\0\end{pmatrix}}} & \left( {{Equation}\quad 13} \right) \\{\begin{pmatrix}X_{W\quad 1} \\Y_{W\quad 1}\end{pmatrix} = {\begin{pmatrix}{{Cos}\quad\theta_{W\quad 1}} & {{- {Sin}}\quad\theta_{W\quad 1}} \\{{Sin}\quad\theta_{W1}} & {{Cos}\quad\theta_{W\quad 1}}\end{pmatrix}\begin{pmatrix}r_{2} \\0\end{pmatrix}}} & \left( {{Equation}\quad 14} \right)\end{matrix}$

From the coordinates calculated with the measurement values, adisplacement in the rotational direction is calculated as follows. Aside including the measurement points P1 (XP1, YP1), W1 (XW1, YW1) isrotationally displaced by β from a side including the teaching positionQ1(XQ1, YQ1), V1(XV1, YV1). This displaced amount β is an angle formedby the vector P1W1 from P1 to W1 and the vector Q1V1 from Q1 to V1,which is calculated as follows: $\begin{matrix}{{\overset{\rightarrow}{P\quad 1W\quad 1} \cdot \overset{\rightarrow}{Q\quad 1V\quad 1}} = {\overset{\rightarrow}{{P\quad 1W\quad 1}}{\overset{\rightarrow}{{Q\quad 1V\quad 1}} \times {Cos}}\quad\alpha}} & \left( {{Equation}\quad 15} \right) \\{\beta = {{Cos}^{- 1}\left( \frac{\begin{matrix}{{\left( {X_{W\quad 1} - X_{P\quad 1}} \right)\left( {X_{V\quad 1} - X_{Q\quad 1}} \right)} +} \\{\left( {Y_{W\quad 1} - Y_{P\quad 1}} \right)\left( {Y_{V\quad 1} - Y_{Q\quad 1}} \right)}\end{matrix}}{\sqrt{\begin{matrix}{{\left( {X_{W\quad 1} - X_{P\quad 1}} \right)^{2}\left( {X_{V\quad 1} - X_{Q\quad 1}} \right)^{2}} +} \\{\left( {Y_{W\quad 1} - Y_{P\quad 1}} \right)^{2}\left( {Y_{V\quad 1} - Y_{Q\quad 1}} \right)^{2}}\end{matrix}}} \right)}} & \left( {{Equation}\quad 16} \right)\end{matrix}$From these equations, the displaced amount β is calculated.

Hereinafter, displacement correcting method is applicable if theaforementioned a is replaced with 1.

(Dust Disposal)

As mentioned above, the present invention provides a thin platetransporting apparatus which is operated in the clean environment. Inthe transporting operation, it is desired to prevent dust generation.First, it is important to generate as little dust as possible. However,as the transporting apparatus includes movable portions, it is difficultto completely eliminate dust generation due to sliding or the like ofthe components. Then, it is preferable to pick up dust from eachdust-generating portion of the transporting apparatus to exhaust thedust to the outside.

FIG. 22 is a partial perspective view for explaining an embodiment toprevent dust pollution in the clean environment. Dust is generated atthe robot 14 (see FIG. 3) placed on the support table 13 and gathered atan exhaust duct 82 a via an exhaust pipe 80 connected to the dust sourceof the robot 14.

The exhaust duct 82 a is connected to the exhaust duct 82 b and furtherconnected via an exhaust pipe 83 which passes through the inside of theupright support member 12 and the inside of the moving table 41, exhaustducts 82 c, 82 d and 82 e, to the outside of the clean environment. Theinside of each of these exhaust ducts 82 a through 82 e is subjected tosuction to the outside and air or atmosphere in the exhaust ducts 82 athrough 82 e is let out to the outside of the clean environment. Inaddition, various electrical wirings are preferably placed in theexhaust pipe 80 and the exhaust ducts 82 a through 82 e.

The exhaust duct 82 a is rotatably supported by the rotational axis 81 aon the support table 13, and further connected to the exhaust duct 82 bvia the rotational axis 81 b. The exhaust duct 82 b is rotatablysupported by the rotational axis 81 c on the upright support member 12.Accordingly, the exhaust ducts 82 a and 82 b are allowed to movefollowing the movement of the horizontal support table 13, or even thevertical movement of the horizontal support table 13, by rotation of therotational axes 81 a to 81 c. This configuration prevents the rotationalaxes 8 a to 81 c from moving above the horizontal support table 13,thereby avoiding the rotational axes 81 a to 81 f from hitting thehorizontal support table 13 and the robot 14, with no contact betweenthe floor and the like and the wiring.

The exhaust duct 82 c is also connected to the moving table 41 by therotational axis 81 d and connected to the exhaust duct 82 d via therotational axis 81 e. The exhaust duct 82 d is connected to the exhaustduct 82 e via the rotational axis 81 f provided on a sliding member 84sliding on the rail 42. As the sliding member 8 a slides and therotational axes 81 d, 81 e and 81 f enables rotational movement, even ifthe support table 41 slides in the horizontal direction, the exhaustducts 82 c, 82 d and 82 e follow its movement thereby discharging theduct to the outside.

Although FIG. 22 deals with only the example of discharging dust fromthe robot 14, it is preferable that dust generated by the verticalsliding movement of the movable table 11 and dust generated byhorizontally sliding movement of the moving table 41 and sliding member84 are all collected to the exhaust ducts 82 a and 82 e to bedischarged.

Other Embodiments

The above description does not deal with the Y axis directionhorizontally transporting apparatus. However, the transporting apparatusof the present invention is preferably provided with a horizontallymoving mechanism as the transporting apparatus is for transporting alarge size sheet (2 m×2 m glass plate or the like) and therefore thedistance between a plurality of cassettes and the distance between aplurality of processing chambers are often long. Specific examples ofthe horizontally moving mechanism of the robot 14 include a system ofhorizontally parallel rails and rack-and-pinion, a cableway system, aball screw rail system, a rail running system, an air-cushion system, amagnetic levitation system and other well-known heavy lifting systems. Adriving source of such a horizontally moving mechanism used hereincludes a servo motor, a stepping motor, a linear motor, a fluidpressure cylinder of hydraulic pressure or air pressure and otherwell-known driving sources.

1. A transporting apparatus, installed in a given clean environment, for transporting a large-sized thin plate from a predetermined takeoff position to a processing chamber, comprising: a pair of upright support members standing at a predetermined interval; at least one horizontal support table liftably cantilevered on the pair of upright support members; lift driving means for lifting the horizontal support table vertically; and a robot placed on the horizontal support table and having horizontally rotating arms for taking up and transporting the thin plate.
 2. The transporting apparatus as claimed in claim 1, wherein the robot drives the horizontally rotating arms to take the thin plate from or back to between the pair of upright support members.
 3. The transporting apparatus as claimed in claim 2, wherein the horizontal support table comprises tilt adjusting means for changing an angle of the robot placed on the horizontal support table with respect to a horizontal plane.
 4. The transporting apparatus as claimed in claim 3, further comprising deflection compensating means for compensating a deflected amount in a vertical direction of the rotating arms and a deflected amount of end effectors provided at respective ends of the rotating arms for taking up and transporting the thin plate.
 5. The transporting apparatus as claimed in claim 4, wherein the deflection compensating means compensates both of the deflected amounts when the end effectors take up the thin plate.
 6. The transporting apparatus as claimed in claim 5, wherein the deflection compensating means comprises deflection storing means for storing deflected amounts in the vertical direction at a plurality of predetermined measurement points involved in movement of a reference point on the rotating arms or the end effectors and, every time the reference point moves to one of the measurement points, the deflection compensating means reads a deflected amount corresponding to a present position from the deflection storing means to compensate the deflected amount.
 7. The transporting apparatus as claimed in claim 6, wherein the deflection storing means stores both a deflected amount due to a self weight and a deflected amount due to holding of the thin plate, and the deflected amount due to the self weight and the deflected amount due to holding of the thin plate are used to change a compensation amount.
 8. The transporting apparatus as claimed in claim 4, wherein the deflection compensating means comprises compensation controlling means for controlling the lift driving means to raise or lower the horizontal support table based on the deflected amount thereby to compensate deflection of the rotating arms or the end effectors.
 9. The transporting apparatus as claimed in claim 4, wherein the deflection compensating means comprises compensation controlling means for controlling the tilt adjusting means to tilt the robot placed on the horizontal support table so as to raise or lower the end effectors or the rotating arms thereby to compensate deflection of the rotating arms or the end effectors.
 10. The transporting apparatus as claimed in claim 4, wherein the deflection compensating means comprises compensation controlling means for controlling the lift driving means and the tilt adjusting means so as to raise or lower the horizontal support table and/or control the tilt adjusting means to performed tilting based on the deflected amount thereby to compensate deflection of the rotating arms or the end effectors.
 11. The transporting apparatus as claimed in claim 1, further comprising: placing position detecting means including a placing position sensor for detecting passage of the thin plate held by the end effectors and calculating means for calculating a displaced amount of the placing position from the reference point based on a detected signal of the placing position sensor; and displacement compensating means for compensating the displaced amount of the placing position based on the calculated displaced amount.
 12. The transporting apparatus as claimed in claim 11, wherein the placing position detecting means calculates a displaced amount in an X axis direction, a displaced amount in a Y axis direction and a displaced amount in a rotational direction from the predetermined reference point and the displacement compensating means compensates the displaced amounts by moving the end effectors in such a direction that the calculated displaced amounts are cancelled.
 13. The transporting apparatus as claimed in claim 1, further comprising moving means for moving the pair of upright support members horizontally.
 14. The transporting apparatus as claimed in claim 1, further comprising a beam for fixedly coupling top portions of the pair of upright support members while the pair of upright support members is held in parallel.
 15. A transporting control method of a transporting apparatus, installed in a predetermined clean environment and having rotating arms and end effectors, for transporting a large-sized thin plate from a predetermined takeoff position to a processing chamber, comprising the steps of: (a) based on position data of accessed position of the rotating arms and the end effectors, calculating a moving amount in a horizontal direction, a moving amount in a vertical direction and driving data of the rotating arms and the end effectors; (b) moving a robot based on the moving amount in the horizontal direction and the moving amount in the vertical direction and driving the rotating arms and the end effectors based on the driving data; (c) reading from storing means deflection data of the rotating arms and the end effectors which are extended; (d) calculating compensation data for compensating a deflected amount based on the deflection data; and (e) controlling to adjust the moving amount in the vertical direction based on the compensation data thereby to compensate the deflected amount.
 16. The transporting control method as claimed in claim 15, the step (e) being replaced with the step (f) of adjusting a tilt angle of the robot based on the compensation data thereby to compensate the deflected amount.
 17. The transporting control method as claimed in claim 15, the step (e) being replaced with the step (g) of adjusting the moving amount in the vertical direction and/or the tilt angle of the robot based on the compensation data thereby to compensate the deflected amount.
 18. The transporting control method as claimed in claim 15, wherein the deflection data read in the step (c) includes deflection data at a plurality of moving points the rotating arms and the end effectors and the compensation data calculated in the step (d) includes compensation data at each of the moving points.
 19. The transporting control method as claimed in claim 18, wherein in the step (c), the deflection data read from the storing means depends on whether the thin plate is held or not.
 20. The transporting control method as claimed in claim 15, wherein in the step (c), read from the storing means is the compensation data calculated and stored in advance based on the deflected amount; calculating of the compensation data in the step (d) is not performed; and processing in the step (e) is performed based on the read compensation data.
 21. The transporting control method as claimed in claim 15, further comprising the steps of: (h) detecting a placing position of the thin plate held by the end effectors; (i) comparing the placing position and a predetermined reference placing position to calculate a displaced amount; and (j) performing operational control to compensate the displaced amount.
 22. The transporting control method as claimed in claim 21, wherein the displaced amount in the step (i) includes a displaced amount in an X axis direction, a displaced amount in a Y axis direction and a displaced amount in a rotational axis direction from the reference placing position, and the operational control in the step (j) is performed to compensate each of the displaced amounts in the step (i). 